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| United States Patent |
6,077,316
|
|
Lund
, et al.
|
June 20, 2000
|
Treatment of fabrics
Abstract
This invention relates to a process for the treatment of fabrics. More
specifically the invention relates to a process for the treatment of
fabrics, which process comprises treating the fabric at elevated
temperatures with an effective amount of a thermostable lipolytic enzyme.
| Inventors:
|
Lund; Henrik (Copenhagen N, DK);
Nilsson; Thomas Erik (Copenhagen .O slashed., DK);
Pickard; Tom (Rossendale, GB)
|
| Assignee:
|
Novo Nordisk A/S (Bagsvaerd, DK)
|
| Appl. No.:
|
008391 |
| Filed:
|
January 16, 1998 |
Foreign Application Priority Data
| Current U.S. Class: |
8/115.6; 510/320; 510/321; 510/392; 510/530 |
| Intern'l Class: |
C11D 003/386; D06M 013/325 |
| Field of Search: |
8/115.6,138
510/320,321,392,530
|
References Cited
U.S. Patent Documents
| 3944470 | Mar., 1976 | Diehl et al. | 195/63.
|
| 4011169 | Mar., 1977 | Diehl et al. | 252/95.
|
| 4421664 | Dec., 1983 | Anderson et al. | 252/94.
|
| 4457760 | Jul., 1984 | Cholley | 8/111.
|
| 4536182 | Aug., 1985 | Tatin | 8/107.
|
| 4712290 | Dec., 1987 | Lindsey | 28/178.
|
| 4876024 | Oct., 1989 | Enomoto et al. | 252/174.
|
| 5736499 | Apr., 1998 | Mitchinson et al. | 510/392.
|
| 5763385 | Jun., 1998 | Bott et al. | 510/392.
|
| 5769900 | Jun., 1998 | Hahn et al. | 8/138.
|
| Foreign Patent Documents |
| WO 88/02775 | Apr., 1988 | WO.
| |
| 93/13256 | Jul., 1993 | WO.
| |
| WO 93/13256 | Jul., 1993 | WO.
| |
| 97/04160 | Feb., 1997 | WO.
| |
Primary Examiner: Fries; Kery
Attorney, Agent or Firm: Zelson; Steve T., Rozek; Carol E., Gregg; Valeta
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of PCT/DK96/00311 filed Jul. 9, 1996
which claims priority under 35 U.S.C. 119 of Danish application serial No.
0845/95 filed Jul. 19, 1995, the contents of which are fully incorporated
herein by reference.
Claims
What is claimed is:
1. A process for enzymatic removal of hydrophobic esters from fabrics,
which process comprises treating the fabric with an amount of a
thermostable lipolytic enzyme effective to achieve removal of hydrophobic
esters from fabric at a temperature of 75.degree. C. above.
2. The process of claim 1, which process is accomplished in the presence of
at least one non-lipolytic thermostable enzyme.
3. The process of claim 2, wherein the non-lipolytic thermostable enzyme is
an amylolytic enzyme, a cellulytic enzyme, or both.
4. The process of claim 1, wherein the thermostable lipolytic enzyme is
derived from a strain of Pseudomonas or a strain of Candida.
5. The process of claim 4, wherein the thermostable lipolytic enzyme is
derived from a strain selected from the group of Pseudomonas fragi,
Pseudomonas stutzeri, Pseudomonas cepacia, and Pseudomonas fluorescens.
6. The process of claim 4, wherein the thermostable lipolytic enzyme is
derived from a strain of Candida cylindracea or a strain of Candida
antarctica.
7. The process of claim 3, wherein the thermostable amylolytic enzyme is an
.alpha.-amylase derived from a strain of Bacillus.
8. The process of claim 7, wherein the thermostable amylolytic enzyme is
derived from a strain selected from the group of Bacillus licheniformis,
Bacillus amyloliquefaciens, and Bacillus stearothermophilus.
9. The process of claim 3, wherein the thermostable cellulytic enzyme is
derived from a strain selected from the group of Humicola, Thermomyces,
Bacillus, Trichoderma, Fusarium, Myceliophthora, Phanerochaete, Irpex,
Scytalidium, Schizophyllum, Penicillium, Aspergillus, and Geotricum.
10. The process of claim 1, which process is carried out in presence of
hydrogen peroxide or a hydrogen peroxide precursor.
11. The process of claim 1, wherein the amount of lipolytic enzyme is from
about 0.01 to about 10,000 KLU/l.
12. The process of claim 7, wherein the amount of lipolytic enzyme is from
about 0.1 to about 1000 KLU/l.
13. The process of claim 7, wherein the .alpha.-amylase is in an amount of
from about 100 to about 10,000 KNU/l.
14. The process of claim 3, wherein the cellulytic enzyme is in an amount
of from about 10 to about 10,000 EGU/l.
15. The process of claim 1, wherein the process comprises a liquor/textile
ratio in the range of from about 20:1 to about 1:1.
16. The process of claim 15, wherein the liquor/textile ratio is in the
range of from about 10:1 to about 5:1.
17. The process of claim 1, wherein the treatment time is within the range
of from about 10 minutes to about 24 hours.
18. The process of claim 17, wherein the treatment time is within the range
of from about 10 minutes to about 55 minutes.
Description
FIELD OF THE INVENTION
This invention relates to a process for the treatment of fabrics. More
specifically the invention relates to a process for the treatment of
fabrics, which process comprises treating the fabric at elevated
temperatures with an effective amount of a thermostable lipolytic enzyme.
BACKGROUND ART
During the weaving of textiles, the threads are exposed to considerable
mechanical strain. Prior to weaving on mechanical looms, warp yarns are
often coated with size starch or starch derivatives in order to increase
their tensile strength and to prevent breaking. The most common sizing
agent is starch in native or modified form, yet other polymeric compounds
such as polyvinylalcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylic
acid (PAA) or derivatives of cellulose (e.g. carboxymethylcellulose (CMC),
hydroxyethylcellulose, hydroxypropylcellulose or methylcellulose), may
also be abundant in the size.
In general, after the textiles have been woven, the fabric proceeds to a
desizing stage, followed by one or more additional fabric processing
steps. Desizing is the act of removing size from textiles. After weaving,
the size coating must be removed before further processing the fabric in
order to ensure a homogeneous and wash-proof result. The preferred method
of desizing is enzymatic hydrolysis of the size by the action of
amylolytic enzymes.
Increasing amounts of cotton wax and other lubricants are applied to yarns
in order to increase the speed of cotton weaving. Also waxes of higher
melting points are being introduced. Wax lubricants are hydrophobic
substances obtained by esterification of long chain alcohols and fatty
acids, and they are predominantly triglyceride ester based lubricants.
After desizing, the wax either remains or redeposits on the fabric and as
a result, the fabric gets darker in shade, gets glossy spots, and becomes
more stiff.
International Patent Application No. WO 93/13256 (Novo Nordisk A/S)
describes a process for the removal of hydrophobic esters from fabric, in
which process the fabric is impregnated during the desizing step with an
aqueous solution of lipase. This process has been developed for use in the
fabric mills only, and is carried out using existing fabric mill
equipment, i.e. a pad roll, a jigger, or a J box.
For the manufacture of clothes, the fabric is cut and sewn into clothes or
garments, that is afterwards finished. In particular, for the manufacture
of denim jeans, different enzymatic finishing methods have been developed.
The finishing of denim garment normally is initiated with an enzymatic
desizing step, during which garments are subjected to the action of
amylolytic enzymes in order to provide softness to the fabric and make the
cotton more accessible to the subsequent enzymatic finishing steps.
For many years denim jeans manufacturers have washed their garments in a
finishing laundry with pumice stones to achieve a soft-hand as well as a
desired fashionable "stone-washed" look. This abrasion effect is obtained
by locally removing the surface bound dyestuff. Recently cellulytic
enzymes have been introduced into the finishing process, turning the
stone-washing process into a "bio-stoning process".
The goal of a bio-stoning process is to obtain a distinct, but homogeneous
abrasion of the garments (stone-washing appearance). However, the dark
shades arising from wax on the fabric greatly reduce the stone-washing
quality, and the stiffness of the fabric causes more rigid folds. As a
result, uneven stone-washing ("streaks" and "creases") occur. In
consequence repair work ("after-painting") is needed on a major part (up
to about 80%) of the stone-washed jeans that have been processed in the
finishing laundries.
The problem of streaks and creases on the finished garments can generally
be traced back to the desizing step. Initially the fabric is stiff and
very often creases have been formed on the garments during packing and
transport. Streaks are rapidly formed at exposed places--such as
creases--if the garment is abraded when still stiff. Therefore it is very
important that denim garments are quickly softened in an efficient
desizing and/or finishing process.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for the
treatment of fabrics, which process improves the finishing quality,
including softness, color distribution/uniformity, stone-wash quality,
etc., and which reduces the need for after-painting of the finished
clothes.
Accordingly the invention provides a process for enzymatic removal of
hydrophobic esters from fabrics, which process comprises treating the
fabric with an effective amount of a thermostable lipolytic enzyme at an
elevated temperature, i.e. a temperature that exceeds the melting point of
the lubricant applied to the fabric.
DETAILED DISCLOSURE OF THE INVENTION
Enzymatic Treatment of Fabrics
The present invention provides a process for enzymatic treatment of
fabrics, by which process hydrophobic esters are removed from the fabric.
Experience from textile finishing processes have revealed that the
currently used processes for removal of hydrophobic esters from the fabric
does not efficiently avoid the problem of streaks and creases on the final
product. Our studies have now shown that this problem is due to the use of
increasing amounts of lubricants of high melting point. In the existing
processes only limited saponification takes place, why these high melting
lubricants are not sufficiently accessible to the enzyme and therefore are
not totally removed from the fabric.
According to our studies it has now been found that the enzymatic treatment
must be carried out at a temperature that exceeds the melting point of the
lubricant. A major part of the presently used lubricants is found to have
melting points above 50.degree. C., and an increasing part of the
lubricants applied to the yarn has melting points as high as above
60.degree. C., or even above 70.degree. C.
Therefore the present invention provides a process for enzymatic removal of
hydrophobic esters from fabrics, which process comprises treating the
fabric with an effective amount of a thermostable lipolytic enzyme at an
elevated temperature, i.e. a temperature elevated to a point exceeding the
melting point of lubricant applied to the fabric.
As described above, enzymatic treatment of fabrics conventionally includes
the steps of desizing the fabric by use of amylolytic enzymes, softening
the garment (including the steps of bio-polishing, bio-stoning and/or
garment wash) by use of cellulytic enzymes, optionally followed by dyeing
the garment, washing the garment, and/or softening the garment with a
chemical softening agent, typically a cationic, sometimes silicone-based,
surface active compound. The process of the present invention may take
place during any of these conventional garment manufacturing steps.
Accordingly, in a preferred embodiment, the process of present invention
may be applied to the desizing step, whereby the invention provides a
process for desizing fabrics, which process comprises treating the fabric
at an elevated temperature with an effective amount of a thermostable
lipolytic enzyme.
In another preferred embodiment, the process of present invention may be
applied to the finishing step, whereby the invention provides a process
for the finishing of fabrics, which process comprises treating the fabric
at an elevated temperature with an effective amount of a thermostable
lipolytic enzyme. The process of the invention for the finishing of
fabrics may in particular be a applied to the step for softening of
garments, to the bio-polishing step, to the stone-washing step or to the
bio-stoning step, and/or to the garment wash step.
Fabrics
The process of the present invention applies to fabrics in general. In the
context of this invention fabrics include fabrics or textiles prepared
from man-made fibers, e.g. polyester, nylon, etc., as well as cellulosic
fabrics or textiles.
The term "cellulosic fabric/textile" indicates any type of fabric, in
particular woven fabric, prepared from a cellulose-containing material,
containing cellulose or cellulose derivatives, e.g. from wood pulp, and
cotton. The main part of the cellulose or cellulose derivatives present on
the fabric is normally size with which the yarns, normally warp yarns,
have been coated prior to weaving. In the present context, the term
"fabric" is also intended to include garments and other types of processed
fabrics. Examples of cellulosic fabric is cotton, viscose (rayon);
lyocell; all blends of viscose, cotton or lyocell with other fibers such
as polyester; viscose/cotton blends, lyocell/cotton blends, viscose/wool
blends, lyocell/wool blends, cotton/wool blends; flax (linen), ramie and
other fabrics based on cellulose fibers, including all blends of
cellulosic fibers with other fibers such as wool, polyamide, acrylic and
polyester fibers, e.g. viscose/cotton/polyester blends,
wool/cotton/polyester blends, flax/cotton blends etc.
The process of the invention is preferably applied to cellulose-containing
fabrics, such as cotton, viscose, rayon, ramie, linen or mixtures thereof,
or mixtures of any of these fibers with synthetic fibers. In particular,
the fabric may be denim. The fabric may be dyed with vat dyes such as
indigo, direct dyes such as Direct Red 185, sulfur dyes such as Sulfur
Green 6, or reactive dyes fixed to a binder on the fabric surface. In a
most preferred embodiment of the present process, the fabric is
indigo-dyed denim, including clothing items manufactured therefrom.
In a most preferred embodiment, the fabric subjected to the process of the
invention is cotton garments, in particular dyed cotton garments or denim
jeans.
Lipolytic Enzymes
The process of the present invention may be performed using any lipolytic
enzyme that is capable of carrying out lipolysis at high temperatures. In
order to efficiently hydrolyse hydrophobic esters of high melting points,
lipolytic enzymes that possess sufficient thermostability and lipolytic
activity at temperatures of about 60.degree. C. or above, are preferred.
Adequate hydrolysis can be obtained even above or below the optimum
temperature of the lipolytic enzyme by increasing the enzyme dosage.
The lipolytic enzyme may be of animal, plant or microbial origin. Examples
of microorganisms producing such thermostable lipolytic enzymes are
strains of Humicola, preferably a strain of Humicola brevispora, a strain
of Humicola lanuginosa, a strain of Humicola brevis var. thermoidea, a
strain of Humicola insolens, a strain of Fusarium, preferably a strain of
Fusarium oxysporum, a strain of Rhizomucor, preferably a strain of
Rhizomucor miehei, a strain of Chromobacterium, preferably a strain of
Chromobacterium viscosum, and a strain of Aspergillus, preferably a strain
of Aspergillus niger. Preferred thermostable lipolytic enzymes are derived
from strains of Candida or Pseudomonas, particularly a strain of Candida
antarctica, a strain of Candida tsukubaensis, a strain of Candida
auriculariae, a strain of Candida humicola, a strain of Candida foliarum,
a strain of Candida cylindracea (also called Candida rugosa), a strain of
Pseudomonas cepacia, a strain of Pseudomonas fluorescens, a strain of
Pseudomonas fragi, a strain of Pseudomonas stutzeri, or a strain of
Thermomyces lanuginosus.
Lipolytic enzymes from strains of Candida antarctica and Pseudomonas
cepacia are preferred, in particular lipase A from Candida antarctica.
Such lipolytic enzymes, and methods for their production, are known from
e.g. WO 88/02775, U.S. Pat. No. 4,876,024, and WO 89/01032, which
publications are hereby included by reference.
Process Conditions
The process of the present invention may be accomplished at process
conditions conventionally prevailing in desizing and finishing processes,
as carried out by the person skilled in the art. The process of the
invention may be carried out using existing desizing and finishing
equipment, e.g. a Pad-Roll, a Jigger/Winch, a J-Box, or Pad-Steam types of
apparatus. However, in a preferred embodiment, the process of the
invention is carried out batch-wise in a washer extractor.
As already described, the process of the invention should be carried out at
a high temperature, i.e. a temperature elevated to a point exceeding the
melting point of the lubricant applied to the fabric, in order to
efficiently hydrolyse the hydrophobic esters (lubricants) of high melting
points. In general, an elevated temperature indicates a temperature of
above 50.degree. C. However, in order to obtain a satisfactory product,
the process may be carried out at a temperature of above 60.degree. C., in
particular above 65.degree. C., above 70.degree. C., or even above
75.degree. C. In a preferred embodiment the process of the invention
should be carried out at a temperature elevated to the range of from about
70 to about 100.degree. C., more preferred the range of from about 75 to
about 95.degree. C., most preferred the range of from about 75 to about
85.degree. C. At such elevated temperatures, the high melting point
hydrophobic esters becomes more readily attacked by the lipolytic enzyme,
thereby leading to a more efficient and rapid hydrolysis.
The enzyme dosage is dependent upon several factors, including the enzyme
in question, the desired reaction time, the temperature, the
liquid/textile ratio, etc. It is at present contemplated that the
lipolytic enzyme may be dosed in an amount corresponding to of from about
0.01 to about 10,000 KLU/l, preferably of from about 0.1 to about 1000
KLU/l.
It is at present contemplated that a suitable liquor/textile ratio may be
in the range of from about 20:1 to about 1:1, preferably in the range of
from about 15:1 to about 5:1.
In conventional desizing and finishing processes, the reaction time is
usually in the range of from about 1 hour to about 24 hours. However, in
the process of the present invention, taking advantage of the elevated
temperature, the reaction time may well be less than 1 hour, i.e. from
about 5 minutes to about 55 minutes. Preferably the reaction time is
within the range of from about 10 to about 120 minutes.
The pH of the reaction medium greatly depends on the enzyme in question.
Preferably the process of the invention is carried out at a pH in the
range of from about pH 3 to about pH 11, preferably in the range of from
about pH 6 to about pH 9.
A buffer may be added to the reaction medium to maintain a suitable pH for
the lipolytic enzyme used, The buffer may suitably be a phosphate, borate,
citrate, acetate, adipate, triethanolamine, monoethanolamine,
diethanolamine, carbonate (especially alkali metal or alkaline earth
metal, in particular sodium or potassium carbonate, or ammonium and HCl
salts), diamine, especially diaminoethane, imidazole, or amino acid
buffer.
The process of the invention may be carried out in the presence of
conventional textile finishing agents, including wetting agents, polymeric
agents, dispersing agents, etc.
A conventional wetting agent may be used to improve the contact between the
substrate and the lipolytic enzyme. The wetting agent may be a nonionic
surfactant, e.g. an ethoxylated fatty alcohol. An example is the Berol
Wash (product of Berol Nobel AB, Sweden), a linear primary C16-C18 fatty
alcohol with an average of 12 ethoxylate groups. The wetting agent may be
added to the lipolytic enzyme solution, or it may be used in a separate
step prior to applying the lipolytic enzyme.
Examples of suitable polymers include proteins (e.g. bovine serum albumin,
whey, casein or legume proteins), protein hydrolysates (e.g. whey, casein
or soy protein hydrolysate), polypeptides, lignosulfonates,
polysaccharides and derivatives thereof, polyethylene glycol,
polypropylene glycol, polyvinyl pyrrolidone, ethylene diamine condensed
with ethylene or propylene oxide, ethoxylated polyamines, or ethoxylated
amine polymers.
The dispersing agent may suitably be selected from nonionic, anionic,
cationic, ampholytic or zwitterionic surfactants. More specifically, the
dispersing agent may be selected from carboxymethylcellulose,
hydroxypropylcellulose, alkyl aryl sulphonates, long-chain alcohol
sulphates (primary and secondary alkyl sulphates), sulphonated olefins,
sulphated monoglycerides, sulphated ethers, sulphosuccinates, sulphonated
methyl ethers, alkane sulphonates, phosphate esters, alkyl isothionates,
acylsarcosides, alkyltaurides, fluorosurfactants, fatty alcohol and
alkylphenol condensates, fatty acid condensates, condensates of ethylene
oxide with an amine, condensates of ethylene oxide with an amide, sucrose
esters, sorbitan esters, alkyloamides, fatty amine oxides, ethoxylated
monoamines, ethoxylated diamines, alcohol ethoxylate and mixtures thereof.
In a particular preferred embodiment, the process of present invention may
be applied in the desizing step. According to the invention it has been
found that waxes and fats yield rather stable complexes, that is not
sufficiently removed in a conventional desizing step. When applying a
thermostable lipase together with a thermostable amylolytic enzyme, a
synergistic effect was obtained. Hydrolysis of the triglycerides result in
an improved starch removal, which leads to an increase in the
accessibility of the natural impurities of the cotton in the subsequent
process steps, in particular the scouring step.
Accordingly, the process may be accomplished in the presence of desizing
enzymes, in particular thermostable amylolytic enzymes, in order to remove
starch-containing size. In another preferred embodiment, the process may
be accomplished in the presence of one or more bleaching agents, in
particular hydrogen peroxide. These well known steps can be carried out as
separate steps before or after the process of the invention, but
advantageously one or both of these prior art processes can be combined
with the process of the invention for removal of hydrophobic esters.
Therefore, an amylolytic enzyme, preferably an .alpha.-amylase, and/or a
hydrogen peroxide or a hydrogen peroxide precursor may be added during the
process of the invention. Conventionally, bacterial .alpha.-amylases are
used for the desizing, e.g. an .alpha.-amylases derived from a strain of
Bacillus, particularly a strain of Bacillus licheniformis, a strain of
Bacillus amyloliquefaciens, or a strain of Bacillus stearothermophilus.
Examples of suitable commercial .alpha.-amylase products are Termamyl.TM.,
Aquazym.TM. Ultra and Aquazym.TM. (available from Novo Nordisk A/S,
Denmark).
The amylolytic enzyme may be added in amounts conventionally used in
desizing processes, e.g. corresponding to an .alpha.-amylase activity of
from about 100 to about 10,000 KNU/1. When an amylolytic is present during
the desizing process of the invention, the pH of the reaction medium may
preferably be within the range of from about pH 5 to about pH 8. Also, in
a desizing process according to the present invention, 1-10 mM of Ca++ may
be added as a stabilizing agent.
In order to carry out bleaching, the reaction medium may typically contain
H2O2 at a concentration of from about 1 to about 30 g/l, and at a pH in
the range of from about 8 to about 11. The reaction medium may also
contain hydrogen peroxide stabilizers, e.g. sodium silicate and/or organic
stabilizers, and a wetting agent/surfactant.
In another preferred embodiment, the process of present invention may be
applied to the finishing step. Accordingly, the process of the invention
may be accomplished in the presence of conventional enzymes and agents for
softening of garments, including conventional enzymes and agents for
bio-polishing, for stone-washing or for bio-stoning, and/or for garment
wash.
Conventional enzymes are in particular cellulytic enzymes. The cellulytic
enzyme may be derived from a strain of Humicola, a strain of Thermomyces,
a strain of Bacillus, a strain of Trichoderma, a strain of Fusarium, a
strain of Myceliophthora, a strain of Phanerochaete, a strain of Irpex, a
strain of Scytalidium, a strain of Schizophyllum, a strain of Penicillium,
a strain of Aspergillus, and a strain of Geotricum.
The cellulytic enzyme may be added in amounts conventionally used in
finishing processes, e.g. corresponding to cellulytic activity of from
about 10 to about 10,000 EGU/1.
Conventional finishing agents that may be present in a process of the
invention include, but are not limited to pumice stones and perlite.
Perlite is a naturally occurring volcanic rock. Preferably, heat expanded
perlite may be used. The heat expanded perlite may e.g. be present in an
amount of 20-95 w/w % based on the total weight of the composition.
Lipolytic Activity
The lipolytic activity may be determined using tributyrine as substrate.
This method is based on the hydrolysis of tributyrine by the enzyme, and
the alkali consumption is registered as a function of time.
One Lipase Unit (LU) is defined as the amount of enzyme which, under
standard conditions (i.e. at 30.0.degree. C.; pH 7.0; with Gum Arabic as
emulsifier and tributyrine as substrate) liberates 1 mmol titrable butyric
acid per minute (1 KLU=1000 LU).
A folder AF 95/5 describing this analytical method in more detail is
available upon request to Novo Nordisk A/S, Denmark, which folder is
hereby included by reference.
Amylolytic Activity
The amylolytic activity may be determined using potato starch as substrate.
This method is based on the break-down of modified potato starch by the
enzyme, and the reaction is followed by mixing samples of the
starch/enzyme solution with an iodine solution. Initially, a blackish-blue
color is formed, but during the break-down of the starch the blue color
gets weaker and gradually turns into a reddish-brown, which is compared to
a colored glass standard.
One Kilo Novo alpha Amylase Unit (KNU) is defined as the amount of enzyme
which, under standard conditions (i.e. at 37.degree. C.+/-0.05; 0.0003 M
Ca2+; and pH 5.6) dextrinizes 5.26 g starch dry substance Merck Amylum
solubile.
A folder AF 9/6 describing this analytical method in more detail is
available upon request to Novo Nordisk A/S, Denmark, which folder is
hereby included by reference.
Cellulytic Activity
The cellulytic activity may be measured in endo-glucanase units (EGU),
determined at pH 6.0 with carboxymethyl cellulose (CMC) as substrate.
A substrate solution is prepared, containing 34.0 g/l CMC (Hercules 7 LFD)
in 0.1 M phosphate buffer at pH 6.0. The enzyme sample to be analyzed is
dissolved in the same buffer. 5 ml substrate solution and 0.15 ml enzyme
solution are mixed and transferred to a vibration viscosimeter (e.g. MIVI
3000 from Sofraser, France), thermostated at 40.degree. C.
One EGU is defined as the amount of enzyme that reduces the viscosity to
one half under these conditions. The amount of enzyme sample should be
adjusted to provide 0.01-0.02 EGU/ml in the reaction mixture.
EXAMPLES
The invention is further illustrated with reference to the following
examples which are not intended to be in any way limiting to the scope of
the invention as claimed.
Example 1
Desizing Experiments
In this example the process of the invention has been applied to a desizing
process for the finishing of denim garments. Two comparative trials have
been carried out, a desizing process accomplished in presence of a
thermostable lipolytic enzyme (the process of the invention), and a
conventional desizing process accomplished in absence of lipolytic enzyme.
The thermostable lipolytic enzyme used in this experiment was Lipase A
obtained from Candida antarctica according to WO 88/02775 (Examples 2 and
10). 200 denim jeans (150 kg in total) were processed. The desizing was
carried out as a batch process using a washer extractor.
Two desizing baths of the following composition were made:
1400 1 of hot water, 75.degree. C.
Surfactant and lubricants, 9.25 1 of Lyoprep.TM. Extra (TS Chemical)
Amylolytic enzyme, 5.5 1 of Bioprep.TM. TBS (TS Chemical)
For carrying out the process of the invention, 0.9 KLU/l of lipolytic
enzyme was added.
The desizing processes were carried out for 20 minutes. After draining off
the desizing bath, the denim garments were rinsed two times in hot water
of 60.degree. C.
Afterwards, the garments of both trials were subjected to a softening
process, using a softening bath of the following composition:
1400 1 of hot water, 60.degree. C.
Cellulytic enzyme, 0.9 kg of Biosoft.TM. NTP (TS Chemical)
The softening processes were carried out for 30 minutes. After draining off
the softening bath, the denim garments were rinsed in cold water.
Finally, the denim garments of both trials were subjected to dyeing using a
solution containing black dyestuff (bi-functional reactives) and
salt/soda. Excess dyestuff was washed off using a detergent solution
(Palodet.TM. RDW), and a silicone softener (3% Palamine.TM. AOS) was
applied to the denim garments.
When comparing the denim jeans from the two trials, the jeans processed
according to the invention were much more soft and a much more even color
distribution. Also, the level of crease marks was reduced significantly,
as was the need for repair work.
Example 2
Desizing and Bio-Stoninig Experiment
In this example the process of the invention has been applied to both a
desizing process and a Bio-Stoning process for the finishing of denim
garments.
The thermostable lipolytic enzyme used in this experiment was Lipase A
obtained from Candida antarctica according to WO 88/02775 (Examples 2 and
10). 150 denim jeans (112.5 kg in total) were processed. The desizing was
carried out as a batch process using a washer extractor.
A desizing bath of the following composition were made:
800 1 of hot water, 75.degree. C.
Surfactant and lubricants, 8 1 of Lyoprep.TM. Extra (TS Chemical)
Amylolytic enzyme, 4.5 1 of Bioprep.TM. TBS (TS Chemical)
Lipolytic enzyme. 1.5 KLU/l
The desizing process was carried out for 20 minutes. After draining off the
desizing bath, the denim garments were rinsed in 400 1 of hot water,
60.degree. C.
Afterwards, the garments were subjected to a bio-stoning process, using a
bath of the following composition:
400 1 of hot water, 60.degree. C.
1 kg perlite (TS Chemical)
Non-ionic surfactant base, 1 1Palanon.TM. BS (TS Chemical)
Cellulytic enzyme, 2 kg 800 NSK (TS Chemical)
Lipolytic enzyme, 3.0 KLU/l
The bio-stoning process was carried out for 40 minutes. After draining off
the bath, the denim garments were subjected to a conventional wash off.
When compared to conventionally processes jeans, the jeans processed
according to the invention showed significantly reduced number of crease
marks, significantly better contrast (reduced back-staining), and absence
of lubricant precipitates.
Example 3
Temperature Influence on Substrate Hydrolysis
This example shows the effect of increasing the temperature of a process
for enzymatic removal of hydrophobic esters from fabrics.
Two different kinds of substrate were employed, a liquid substrate
(reference) and a solid substrate. A reaction mixture was made based on
14.75 ml de-ionized water and 0.25 g stabilized glyceride substrate. The
liquid substrate was a stabilized olive oil emulsion (available from Sigma
Diagnostics), and the solid (non-melted) substrate was a commercial
textile lubricant, TecWax.TM.. To avoid product inhibition an additional
200 mmol of CaCl.sub.2 was added to the reaction mixture.
The experiments were made at a pH of 7 that was held constant (ph-stat
experiments) by titration with 10 mM NaOH using a TitraLab ABU91 equipment
from Radiometer A/S (Copenhagen). When this ph-stat condition was reached,
5 LU of lipase (Lipase A obtained from Candida antarctica according to WO
38/02775, Examples 2 and 10) was added, and the extent of hydrolysis
within the following 30 minutes was evaluated from the net consumption of
NaOH.
Trials were made at 30, 40, 50, 60 and 70.degree. C., respectively, and the
results are presented in Table 1, below.
TABLE 1
______________________________________
Temperature Influence on Substrate Hydrolysis
Substrate
30.degree. C.
40.degree. C.
50.degree. C.
60.degree. C.
70.degree. C.
______________________________________
Olive oil
+++ +++ +++ +++ ++
TecWax 0 0 + +++ +++
______________________________________
0 denotes that no activity can be measured with the method employed.
+ denotes a small yet detectable hydrolysis (approx. less than 0.1 mmol
NaOH consumed (per 5 LU lipase) within 30 minutes).
+++ denotes significant hydrolysis more than approx. 0.1 mmol NaOH
consumed (per 5 LU lipase) within 30 minutes.
The triglycerides used today in the textile industry are normally composed
of modified tallow with a melting point between 50-60.degree. C. For the
commercial lubricant employed in this example, a melting point of
51.degree. C. was determined by means of differential scanning
calorimetry. As gathered from the above results, the lipase does not
hydrolyze the glyceride substrate to a significant extent when the
reaction temperature is below the melting point of the substrate.
Because many of the lipases known in the art loose a substantial part of
their activity when employed at elevated temperatures, the use of lipases
with high thermal stability are essential for this application, in part to
give a reasonable extent of hydrolysis, and in part to make the technical
process robust.
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